The invention relates to an elevator installation which has an elevator car and a counterweight which are suspended and driven by flat-belt-type suspension means arranged in parallel. Present on the counterweight and/or on the elevator car are suspension-sheave systems which, together with a traction sheave and the suspension means, form a suspension system. This suspension system has a reeving factor of at least 2:1, and the suspension means, or more specifically their center lines, are arranged in parallel vertical planes which run diagonally to the main horizontal axes of the counterweight and/or of the elevator car.
From published International application WO 99/43593 an elevator system is known which has a drive motor arranged above, and in which the elevator car and the counterweight are suspended and driven by several flat belts arranged in parallel. FIG. 5 in WO 99/43593 shows an exemplary embodiment in which the flat belts which form the suspension means support the elevator car in the form of an undersling, the suspension means being arranged in parallel vertical planes which run diagonally to the main horizontal axes of the elevator car and of the counterweight, i.e. also diagonally to the walls of the elevator hoistway. The axles of the traction sheave, of the suspension sheaves mounted underneath the elevator car, and of the suspension sheaves on the counterweight, are aligned at right angels to the aforementioned planes of the suspension means and therefore also diagonally to the aforementioned main axes of the elevator car and of the counterweight.
An elevator car as disclosed in FIG. 5 of WO 99/43593 has a disadvantage as described below.
Passed around the suspension sheave present on the counterweight are several flat belts arranged in parallel, which can have the consequence that the suspension sheave must have a width which is substantially greater than the width of the counterweight. Because of the diagonal alignment of the suspension sheave axle relative to the main horizontal axes of the counterweight, which is necessary for the illustrated flat-belt suspension, the suspension sheave of the counterweight can require a building space which exceeds the width (thickness) of the counterweight. This prevents optimal utilization of the available hoistway cross section to accommodate a largest possible floor surface of the car, or requires for a given floor surface of the car a larger hoistway cross section.